ES2897450T3 - System for position and/or line monitoring in an energy chain - Google Patents

Abstract

Monitoring system for monitoring the position of a cable chain (1) for guiding at least one line between a base and a drag lug (4) that can move relative to it, comprising: - a cable chain ( 1) which can be moved along a travel path and in this respect forms a movable branch (1B) with a connection end for the drag lug (4), a static branch (1A) with a connecting end connection for the base and a deflection curve (1C) between the two branches (1A; 1B); and - a monitoring device with at least one transmitter arranged on the cable chain (1), which evaluates a signal (11; 51) generated by the transmitter to monitor whether an error condition occurs during operation of the cable chain (1); the transmitter presenting an electrical indicator conductor (12; 22; 42; 52) guided by the cable-carrying chain (1), which runs at least along a predominant length of the mobile branch (1B); - the monitoring device comprises a circuit (14; 24; 44; 54) connected to the indicator conductor (12; 22; 42; 52), which detects an electrical magnitude by means of the indicator conductor (12; 22; 42; 52) ; characterized in that the monitoring system also has a generator (48; 55), which generates a time-varying drive signal, in particular an alternating current or pulse signal, and the circuit (14; 24; 44; 54) in the indicator conductor (12; 22; 42; 52) detects as a magnitude an electrical parameter sensitive to geometry with respect to the spatial position of the indicator conductor (12; 22; 42; 52).

Description

DESCRIPTION

System for position and/or line monitoring in an energy chain

The invention generally relates to a system for position and/or line monitoring in a cable chain. The invention relates in particular to a monitoring system for a cable chain, which serves to dynamically guide at least one line, such as, for example, a cable, flexible tube or the like, between a base and a relatively mobile drag lug. the same. In this respect, a generic system comprises, on the one hand, an energy chain that can be moved along a displacement path and, in this respect, in a variable way, depending on the position of the drag lug, forms a mobile branch with a connection end for the trailing heel, a static branch with a connection end for the base and a deflection curve between the two branches. Furthermore, the system comprises a monitoring device with at least one transmitter arranged on the energy chain, the monitoring device evaluating a signal generated by the transmitter to monitor whether an error condition occurs during operation of the energy chain.

Different systems of this type are already known. Thus, for example, patent applications WO 2004/090375 A1 and WO 2013/156607 A1 disclose systems with a force transducer between the drag bead and the cable chain to monitor whether the forces that occur are within a tolerance interval.

Patent application WO 2015/118143 A1 discloses a system with a mechanical action transmitter, which detects, by means of an activation cord, damage to the cable chain. A similar system is known from JP 2009052714 A, in this case a break detection system with an optical fiber is proposed, ie a break can be detected by the amount of light.

The aforementioned systems have the disadvantage that in principle they only detect damage that has already occurred. In particular, they do not thereby allow prospective maintenance or predictive maintenance (in English, "predictive maintenance").

In patent application EP 1 521 015 A2 a monitoring system has been described which can allow condition-based preservation. In this sense, for example, the degree of damage to the energy chain is determined to a limited extent locally by electromechanically acting wear elements, eg damage-related wear on the narrow side of a chain link. However, this system does not provide any information on the current position of the energy chain or on the status of a guided line.

In the utility model DE 20 2004 005 858 U1, the applicant has proposed a monitoring system that provides information on the current position of the cable chain, which can also detect error conditions. To this end, it has been proposed to arrange sensors on the chain links that generate signals that depend on the pivoting position of the chain link. As sensors, for example, so-called mercury rocker switches have been proposed, which react to position changes and, as rocker sensors, indicate the spatial position of the chain link in each assigned case. This solution is technically complex, in particular with regard to mounting or manufacturing, since a plurality of sensors have to be mounted and wired.

In contrast, in patent EP 2235 396 B1 it is incidentally proposed to arrange external electrical contact means along the travel path, for example in the guide channel of the cable chain, with which the cable chain should come into contact. contact in the event of a deviation caused by a fault.

Document EP1521015A2 discloses a cable chain extruded in a single piece of plastic. The chain links of this energy chain are separated from each other by spacer grooves and are connected to each other via connecting webs. They surround a cable channel for cable routing. Embedded in the chain are electrical lines in the form of wires, which, like the chain itself, continuously deform alternately during the movement of the chain. The lines are designed in such a way that they break after a predetermined number of alternating deformations, which represents a critical number for chain wear. As a result, an electrical circuit to which a chain drive unit is connected is interrupted. If one of the lines breaks, the drive equipment for the chain is automatically switched off. In addition, a connected signaling equipment sends a signal.

It is also known to determine the expected service life of cables in energy chains by laboratory testing on the basis of a characteristic increase in conductor resistance, which typically only occurs after many hundreds of thousands or millions of cycles of operation. proof.

Finally, from patent US 7,023,217 B1, in this context a monitoring system is already known that allows implementing a detection of the state of wear of electrical conductors, in particular of flat cables, for example, in a flexible feeder cable. In this sense, several conductors of the flat cable are measured by a complex circuit arrangement with a relay multiplexer and a precision voltmeter. However, due to complex circuit layout and the connection technology proposed at both connection ends of the energy chain, this solution is not very suitable for use in practical or active operation of an energy chain.

According to an object of the present invention, an easy-to-mount system should be proposed that provides a statement about the current spatial position of the energy chain. In this regard, the system should in particular protect against damage caused by unwanted climbing or rearing. This objective is solved by a system according to claim 1.

In the case of a generic monitoring system according to the preamble of claim 1, provision can be made for the transmitter to have an electrical indicator conductor guided by the energy chain, which runs along at least a predominant length of the moving string. In this regard, it can further be provided that the monitoring device comprises a circuit, which is connected to the display line for detecting at least one electrical variable via the display line, and the monitoring device can comprise a preferably programmable evaluation unit, which compares the signal depending on the detected variable, for example immediately or optionally after signal processing, with at least one previously stored reference value or tolerance interval.

The term transmitter is used in this sense with a very general meaning, in particular as a synonym for sensor component (ie it does not mean, for example, encoder or the like).

In this respect, the evaluation unit can allow application-specific modular adaptation of the monitoring device, even in the case of a constant topology of the detection circuit, for example, through appropriate programming of the evaluation functions and /or the variable storage of the operating parameters in the evaluation unit. In this regard, the evaluation unit can also enable, among other things, a modularly constructed system with several circuit modules, which, in particular depending on the desired monitoring aspect, are each structurally identical and regardless of the indicator conductor used, for example, one type of circuit for position monitoring and one type of circuit for line monitoring. In addition, flexible consideration of various variables, such as application and runtime dependent parameters, as well as environmental parameters, e.g. number of cycles, temperature, etc. The detection circuit and the evaluation unit can be integrated as modules in a common assembly, optionally also on a printed circuit board, or they can be configured spatially separately.

In particular, for the implementation of an actual measurement or a metrological detection of the electrical quantity, it can be provided that the circuit comprises a measuring device connected on the input side to the indicator conductor in order to detect the electrical quantity, in particular an electrical parameter. of the indicator conductor, through quantitative measurement, and to provide a signal on the output side for the evaluation unit that depends on it. In this connection, the term measurement can be understood in the sense of the definition in DIN 1319.

In particular, but not only in the case of metrological detection, the evaluation unit can have an integrated logic circuit, such as, for example, a microcontroller or the like, with a reference value memory for the evaluation of the detected quantities or either measured against one or more reference values, eg a tolerance interval. In this connection, the measuring device can be configured as desired, either completely analog, partially analog and partially digital, or purely digital. Due to the preferably programmable logic circuit, the evaluation unit can be optionally and modularly adapted to the measuring circuit. The reference value memory can also be embodied separately from the actual evaluation unit, for example when the latter queries the former as required, but is preferably part of the logic circuit.

The modular type of construction allows, for example, a resistance or impedance measurement adapted to the application, regardless of the indicator conductor used; since the absolute value depends, among other things, on the total length of the indicator conductor, which should run along at least a predominant length of the moving string, i.e. the expected measured values depend to a large extent on the application in which the energy chain is used. By means of continuous resistance or impedance measurement, it is possible to predict relatively reliably, for example, an impending failure of the wires due to a fatigue break in an electrical cable. Contrary to what is proposed, for example, in US Pat. No. 7,023,217 B1, with the proposed evaluation unit it is not necessary to provide a redundant power chain or idle line, merely for reference purposes.

The at least one indicator conductor preferably extends over at least a predominant proportion of the length of the energy chain, in particular over the entire length proportion of the energy chain that can be displaced during operation. In this case, the indicator conductor preferably extends over at least half of the length of the cable chain, situated close to the drag lug or adjoining it, since the stress caused in this case by the pulling and pushing forces, wear is generally greater and atypical behavior occurs there more frequently. In this regard, the indicator conductor should extend at least over the critical longitudinal section of the energy chain, typically the first third viewed from the drag stub.

The electrical indicator conductor can be implemented separately, as an additional line or, for example, as a component of a cable used in the application. In both cases, the indicator conductor can be guided, for example, in the same way as a live line and in the energy chain, in particular continuously from one end of the energy chain to the other and, if necessary, also in loop back to one end.

According to the invention, a monitoring system is provided for monitoring the position of a cable chain according to claim 1, for example for ascending monitoring during the back and forth movement of the cable chain.

According to the invention, the system according to the preamble of claim 1 for the resolution of the aforementioned objective has at least one or more electrical indicator conductors guided by the energy chain as a transmitter, which runs at least along a predominant length of the mobile branch. In this sense, the monitoring device also has a circuit connected to the indicator conductor, which detects an electrical quantity via the indicator conductor. In addition, the circuit has a generator, which generates a time-varying drive signal, in particular an alternating current or pulse signal, which is supplied to the indicator conductor or to an additional conductor that influences it electromagnetically, for example inductively. .

As a result, the circuit in the indicator lead can detect as a magnitude a geometry-sensitive electrical parameter with respect to the spatial position of the indicator lead. In the sense of electrodynamics, the time-varying electromagnetic field induced by the generator, in the case of a suitable arrangement, causes an interaction with the indicator conductor, which is a function of the spatial position of the indicator conductor, i.e. also the position of the cable chain. In this way, information about the current position of the cable chain can be obtained from the geometry-sensitive electrical parameter, in particular an abnormal course, such as, for example, an undesired rise or rearing of the mobile branch. In such an embodiment, the indicator conductor can form, for example, a receiving coil, which is preferably displaceable with the moving string. In this connection, the detection circuit may function according to a metal detector principle. The circuit together with the receiving coil and, if necessary, additional coils is preferably implemented according to the principle of a BFO metal detector or pulse induction metal detector, the construction of which is known per se to those skilled in the art . The principle of a VLF metal detector would also be conceivable, but it has a shorter range.

In this connection, in particular, an additional transmitter coil can be guided in the energy chain, in which the generator feeds the drive signal to generate a measurable signal on the indicator conductor. This signal can then be detected as a quantity by the circuit and can allow an inference about the spatial position of the indicator conductor.

According to Maxwell's equations, these solutions are geometry sensitive, e.g. on the one hand due to other electromagnetically active components in the environment of the energy chain (boundary conditions), but e.g. on the other hand also due to coupling or back-coupling, which depends on the current relative position and spatial orientation of the branches with respect to one another, in the receiving coil, i.e. the indicator conductor (cf. mutual induction), through self-induction which depends on the spatial geometry and, where appropriate, also through a superposition of the two aforementioned position-dependent effects on the electromagnetic field.

Despite the detection principle, provision can be made for the indicator conductor to form a coil and for the circuit to detect an inductive parameter. In this sense, at least one coil, in particular the receiving coil and/or the emitting coil, can run in a longitudinal section, close to the drag heel, of the moving branch in order to improve the last effect mentioned above. Alternatively or additionally, the energy chain can also be guided in a ferromagnetic guide channel, which corresponds to the first effect mentioned above on the magnitude that can be detected on the indicator conductor.

In order to detect as a magnitude a geometry-sensitive parameter with respect to the spatial position of the indicator conductor due to electrodynamics, there are different possibilities which, for example, can also be based on antenna technology.

For example, provision can be made for the indicator conductor to be arranged as a loop antenna, in particular on the energy chain, for the generator to supply the excitation signal to the indicator conductor and for the circuit to detect a geometry-sensitive electrical parameter as a magnitude. of the antenna, for example, resonance frequency or the like.

Alternatively, the indicator conductor can be arranged, for example, as a dipole antenna, in particular on the Cable chain. By feeding the excitation signal to such an indicator conductor by the generator, the circuit can also detect as a magnitude an electrical parameter sensitive to the geometry of the antenna, for example a standing wave ratio (SWR). ), a reflection factor or the like. Suitable circuits for this are known per se, such as a standing wave meter ( SWR meter ), a network analyzer, etc.

In all of the aforementioned exemplary embodiments, a variable is detected which depends on the spatial position of the indicator conductor and thus also of at least one part of the energy chain. In this way, information about the current position or the displacement posture of the energy chain can be obtained in a simple manner, in particular by comparing the size with a predetermined learned tolerance field.

According to a second additional independent aspect, a monitoring system for monitoring the condition of a cable in a cable chain is proposed. This aspect can be combined with a monitoring system according to the first aspect, inter alia since at least one indicator conductor is provided as a central element.

According to the second aspect, a monitoring system is provided for monitoring the condition of a cable which is guided in an energy chain between a base and a trailing lug relatively movable thereto.

The second independent aspect concerns the monitoring of the state of a cable that is guided in a cable chain between a base and a trailing lug relatively movable thereto. A corresponding system may comprise a generic energy chain, which can be moved along a path of movement and, in this respect, forms a generally movable first branch, a generally static second branch and a deflection curve between the two branches. Apart from that, it has in particular a monitoring device with at least one transmitter arranged on the energy chain, which evaluates a signal generated by the transmitter to monitor whether an error condition occurs during operation of the energy chain. In this regard, the transmitter can have two electrical indicator conductors guided by the energy chain, which run along a predominant length of the moving branch or, for example, along the entire length, and the monitoring device can comprise a circuit with a measuring device for the measurement of resistance or conductance. It can be provided that in each case a proximal end point of each of the two indicator conductors, i.e. the end points at one of the two connection ends of the energy chain, are connected to the measuring equipment and the in each case other end or distal points of the two indicator leads are shorted. These endpoints of the two indicator conductors may terminate at a given longitudinal position of the energy chain or preferably at the other distal connection end of the energy chain. Due to the short circuit, the conductors can form a measurement loop, the resistance or conductance value of which can be measured via the measuring equipment. For example, a continuous measurement loop without interruption by a separate short-circuit component is conceivable, i.e. one indicator line represents the path to or from proximal to distal and the other indicator line represents the path back or vice versa. . However, a separate short-circuit component is more practical, as this allows the use of existing multi-core cables and does not require a continuous measurement loop.

The central idea here is that the circuit can comprise a measuring device for measuring a resistance value or a conductance of the indicator conductor and that the indicator conductor can be designed in the form of a loop, so that can be measured on one side at the same connection end of the energy chain. In addition, the measured resistance value can be increased through the forward and reverse curve and the effect caused by wear can be almost doubled, which simplifies a reliable early detection of a wire or strand break.

Furthermore, provision can be made for the monitoring device to comprise an evaluation unit, which has an integrated logic circuit and a reference value memory. In this case, the logic circuit can receive an output signal from the measuring device and use it for comparison with at least one reference value previously stored in the reference value memory.

The circuit or measuring device for this can be implemented in particular for voltage measurement in four-conductor technology, similar to the principle of a Thomson bridge (also called Kelvin bridge), with a built-in reference resistor in the technology of four leads, a differential amplifier, and an analog-to-digital converter to accurately detect resistance values even smaller than an indicator line. Such a development provides, for example, that a separate instrumentation amplifier of its own is provided for the or each measuring loop, which is connected on the input side to both end points of the display lines and on the input side. output to an analog-digital converter, in particular an analog-digital converter integrated in the logic circuit is connected. Preferably, a reference resistor is switched in series with the measurement loop(s), a constant current source feeding a measurement current through the measurement loop(s) and, if applicable, a reference resistor. Using the reference resistance, the voltage measurement in four-phase technology leads, similar to the principle of a Thomson bridge, can also detect a very small resistance of the measurement loop of the two indicator leads with sufficient accuracy.

Preferably, the measurement loop formed by the forward and backward guided two-part indicator conductor is formed by two additional measurement wires specifically intended or assigned in an active multi-core supply cable, the remaining cores of which serve the purpose actual supply, for example data transmission or power supply.

The dedicated measurement leads are preferably short-circuited by means of a short-circuit component at the trailing stub-side end and are connected to the circuit measurement equipment at the base-side end, i.e., the circuit and, given In this case, the evaluation unit can simply be arranged in the stationary part of the installation. The connection mode can optionally also be implemented the other way around if the circuit is provided on the drive side, which is particularly useful for an evaluation unit arranged on the displaceable machine part.

For monitoring the condition of a cable, it is particularly advantageous if the measuring wires, which form the essential part of the indicator conductors, are twisted together or possibly twisted together with other live wires in a supply cable used for as determined during operation. Therefore, the informative strength of the detection is adjusted as realistically as possible to the deterioration of the active threads that are actually being monitored. In this regard, the measurement wires can be made, in particular, structurally identical to at least one wire active during operation and can be braided or intertwined analogously to it. In particular, the measurement threads can be made in a structurally identical manner with respect to the thread most susceptible to wear. In the case of lines with a large cross section, it is also conceivable to make the measuring wires with a smaller cross section and interpolate to the state of a stronger main wire, in particular by means of the evaluation unit. Preferably, the integrated logic circuit or, particularly preferably, the evaluation unit has an operating input for storing a resistance or conductance value measured by the measuring device during startup as a reference value. Therefore, the standard value for the original or wear-free state of the measuring loop or indicator conductor can also be easily defined by the end user himself. As a result, the monitoring device is inherently programmed in an application-specific manner without, for example, the length of the cable chain or similar data having to be known.

In particular in connection with the last-mentioned feature, it is advantageous if the evaluation unit is programmed to trigger a warning message when the resistance value or the conductance of the indicator conductor deviates from the reference value by a predetermined amount, in particular an amount in the range of 15-25% of the reference value. By means of an empirically determined quantity as a threshold value, monitoring of the cable can be performed only with the knowledge of the original normal value for the resistance value or the conductance.

The following refinements are advantageous for all of the above aspects, ie also for position monitoring and/or line status monitoring.

The evaluation unit preferably has a memory for application data and comprises logic which evaluates the signal output by the circuit as a function of the stored application data. This type of construction allows, for example, the storage of nominal values or a tolerance field. In this way, for example, the reference data can be registered with the circuit in an initialization process in the case of the procedure according to the normal determination of a new energy chain and stored in the evaluation unit. The application-specific and/or position-specific reference data can also be obtained, for example, from a test laboratory and previously stored in or transmitted to the evaluation unit.

In particular, in the last-mentioned case, the evaluation unit can have an input through which the current location of the trailing lug is detected. This allows a currently valid reference value to be read from memory as a function of location, which is particularly important for geometry-sensitive quantities.

The evaluation unit can comprise a communication interface, eg a WLAN interface, for connection to a higher-order system in order to read or send data, eg for initialization, for maintenance purposes or for manufacturer data collection.

In particular, for accurate metrological detection, it is advantageous if the monitoring device has a temperature sensor for temperature normalization. This can be provided, for example, as a component of a modular evaluation unit.

In order to increase modularity, the device, as part of the circuit or evaluation unit, can have a logic circuit, in particular a microcontroller, ASIC (Integrated Circuit for application-specific")), DSP (Digital Signal Processor) or the like, which digitally processes the detected electrical magnitude, in particular for comparison with a reference value from a reference value memory. This results it is particularly advantageous if the circuit detects the electrical magnitude in an analog manner.

The circuit can detect the electrical quantity constant in time or discrete in time at regular or random time intervals in the continuous operation of the energy chain. In this connection, a filter, in particular a mean or peak value filter, is preferably provided in the circuit or in the evaluation unit in order to filter out irrelevant fluctuations, for example due to electromagnetic interference and the like.

The device, in particular as a module, can be arranged stationary on the base, the indicator conductor being connected to the circuit on one side at the connection end for the base.

The basic principle of the monitoring system proposed here is suitable for continuous operation, both for use for monitoring the spatial course of the energy chain during continuous operation and for monitoring the status of a data or supply cable. of an energy chain during continuous operation. The systems serve in particular for preventive maintenance and/or safety shutdown.

Further advantageous features and effects of the invention are explained in more detail below by means of some preferred embodiments with reference to the accompanying drawings. In this regard, they show:

FIGURES 1A-1B: as a schematic diagram in side view (FIGURE 1A) and schematic cross-section (FIGURE 1B), a first embodiment of a monitoring system according to one aspect;

FIGURES 2A-2B: as a schematic diagram in side view (FIGURE 2A) and schematic cross-section (FIGURE 2B), a second exemplary embodiment of a monitoring system according to a variant;

FIGURE 3: a schematic of a tolerance field within which an electrical magnitude should be found on the indicating conductor;

FIG. 4: as a schematic diagram in side view, a third exemplary embodiment of a monitoring system;

FIG. 5: as a schematic diagram in side view, a fourth embodiment of a monitoring system according to a further variant, with a wireless communication interface to a communication module;

FIGURES 6A-6B: As a schematic diagram in side view (FIGURE 6A), a monitoring system with a wireless communication interface to a communication module, and as a separate circuit module (FIGURE 6B) for monitoring the status of a cable in an energy chain; and

FIGURE 7: A photo of a partially exposed power supply cable with twisted wires.

Throughout the drawings, the same reference symbols designate features with an equivalent nature or action. For ease, repetitions are avoided.

In FIGURES 1-7 an energy chain is shown, generally designated as 1, with a stationary branch 1A, also called a lower branch in the case of a horizontal arrangement, a mobile branch 1B, also called an upper branch in the case of a vertical arrangement. horizontally, as well as (as a variable location transition in between) a movable, roughly U-shaped, 1C deflection curve that ensures a predefined radius of curvature. In this case, a so-called "sliding" cable chain 1 has been shown, that is, not cantilevered, for long travel paths, typically > 3 m. In the case of such energy chains 1, the mobile strand 1B can slide or roll away from the stationary strand 1A. The slide shoes or slide rollers known per se have not been shown. In this regard, the predefined radius of curvature of the deflection curve 1C, to protect the guided lines (not shown), is considerably larger than the contact distance between the branches 1A, 1B. In principle, however, the invention is also suitable for cantilever energy chains or vertical applications (not shown). The end area of the stationary branch 1A forms a first connection point of the cable chain 1 and is fixed to a base stabilized with respect to the environment, which forms the fixed point 2 of the cable chain 10. The end area of the mobile branch 1B forms a second connection point of the cable chain 1 and is fixed to a drag lug 4, which is movable relative to the fixed point 2, namely it is connected to the movable part to be supplied, for example from an industrial machine or facility.

In a manner known per se, the trailing lug 4 moves according to the double arrows drawn in FIGURES 1-7 in a forward and backward direction and pulls or pushes, in this regard, the energy chain 1. In FIGURES 1-7, the trailing heel 4 and thus the posture of the cable chain 10 is represented purely by way of example, only for illustration as instantaneous or momentary intermediate positions. The energy chain 1 is designed for almost flat movement along the forward and backward direction, that is, with the legs 1A, 1B remaining in parallel, and is essentially composed of chain links (not further shown). detail) which, for example, can be arranged against each other about parallel pivoting axes that can be pivoted perpendicular to the plane of FIGURES 1-7. In the case of all embodiments, the energy chain 1 can be laterally guided in a guide channel 5 schematically shown in more detail in FIGURE 1B.

A rare but particularly possible error condition (indicated as "lightning") in the case of fast-running or long power strings 1 is here shown purely schematically and in exaggerated representation only in FIGURE 1A and FIGURE 2A, undesirably ascending a partial area of the mobile branch 1B. FIGURE 6A shows, by way of example, a normal course of the cable chain 1.

In the exemplary embodiment according to FIGURES 1A-1B, a monitoring system 10 is shown with an electrical indicator conductor 12 guided along the two branches 1A, 1B and through the deflection curve 1C of the energy chain 1 as elements. transmitter centers. The single indicator conductor 12 is arranged as a cross-radiating dipole array or single dipole antenna and is connected to a circuit 14 at the end node at base 2. The circuit 14 comprises a signal generator which feeds an excitation signal signal, for example, a sinusoidal alternating current signal with a frequency of a few MHz, to the indicator lead 12. Apart from that, the circuit 14 has a standing wave measuring device (not shown), which detects as electrical magnitude the standing wave ratio (SWR) via the indicator line 12. The SWR depends on the spatial position of the indicator line 12 and thus of the energy chain 1, in particular the moving string 1B. The detection of the SWR allows recognition of an error condition (indicated as "lightning") compared to a theoretical course of the SWR learned during commissioning (cf. 30 in FIGURE 3). Instead of the standing wave measuring device, for example, a network analyzer or a simpler circuit for measuring the reflected wave at a constant excitation frequency is also suitable. On the output side, circuit 14 is connected to an evaluation unit 6 which, for example, evaluates an output signal, indicating the SWR, from circuit 14 and triggers an emergency stop at an early stage in the event of a fault. an error condition.

In the variant according to FIGURES 2A-2B, the indicator conductor 22 forms a measurement loop or loop antenna and is arranged in the circuit 24 as an inductive part of an RLC resonant circuit. The two endpoints of two measurement wires 22A, 22B at base 2 are directly connected to the remaining resonant circuit components of circuit 24. The distal endpoints, for example, at trailing heel 4, are short-circuited by a low ohm short circuit 23, as shown in FIGURE 2B. Since the induction in this case also depends on the geometry, the circuit 24 can recognize a change in the induction of the measuring loop coil as a measured value 30 compared to a normal course between two tolerance curves 31, 32, as schematically indicated in FIGURE 3. This can be done by means of a microcontroller 25 as part of the circuit 24 or in the evaluation unit 6, for example, through the recognition of an abnormal jump in the detected electrical magnitude of the indicator conductor 22 of two parts.

FIGURE 4 shows a variant of the supervision system 40 for the detection of an unexpected change in the heterodyne frequency by means of the superposition of two resonant circuits. In this case, the indicator conductor 42 also forms a loop or coil of two measuring wires 42A, 42B, which are led from the base 2 to the drag lug 4 in the energy chain and are bridged at the drag lug by the short circuit component 43.

The circuit forms a first measurement resonant circuit 46, with a capacitor (C2) and measurement loop 42 as inductance, which is subjected to a sinusoidal signal via a signal generator 48. A reference resonant circuit 47 simulates, depending on a measurement cycle or learning during start-up, the normal behavior of the measurement resonant circuit 46 in the case of the course according to what is determined from the cable chain 1, its behavior depending on the location of the heel of drag 4. The simulation can be implemented, for example, via a stored sequence of measured values or an adjustable oscillator in a microcontroller 45. By means of a mixer step 49, a heterodyne frequency is then generated on the basis of the detected oscillation in the measurement resonant circuit 46 and the simulated oscillation that depends on the position of the reference resonant circuit 47. A comparison is then made of the heterodyne frequency generated or else simulated by the mixer step 49, for example, with a tolerance field 31, 32 depending on the location X of the drag stub 4, as shown schematically in FIGURE 3. This variant is based eg in the principle of a metal detector, and can be used in particular with a guide channel 5 made of ferromagnetic sheet steel or the like.

In a variant not shown in more detail, in addition to the measurement loop formed by the measurement wires 42A, 42B, a separate excitation or transmitter coil can also be provided, for example according to the principle of other types of metal detectors.

FIGURE 5 shows an additional inductive detection monitoring system 50, the guide channel 5 acting as a "ferrite core". The loop-shaped indicator conductor 52 is excited and measured by means of an oscillator 55 as signal generator. A demodulator 56 guides the detected signal towards a discriminator or hysteresis comparator 57, and this further towards a final step, which provides an output signal 51 for the evaluation unit 6. In this sense, the normal values learned or the tolerance curves 31, 32 can be stored in the evaluation unit 6 during commissioning or via a data connection such as, for example, WLAN with a communication module 7.

The monitoring systems 10, 30, 40, 50 described above allow, in particular by means of electromagnetic interaction, the detection of a deviation in the position of the cable chain 1 from its nominal theoretical course.

A separate additional aspect is described below, namely a system 60 for monitoring the wear of electrical conductors or wires in a supply cable of an active energy chain in order to give early warning of a break. of pending cable.

The circuit module 64 has two status displays, eg (ACTIVE, ERROR: FIGURE 6B) and a pushbutton (SET: FIGURE 6B) for programming a nominal resistance value into a memory register in a microcontroller 65 of the module. of circuit 64.

An instrumentation or differential amplifier (OpAmp) 66 is directly connected to the end nodes of two measurement wires 62A, 62B, which form an indicator conductor 62 in the form of a loop in the energy chain 1, which is short-circuited at the drag stub 4 through a component 23. The output of the instrumentation amplifier 66 is connected to the input of an analog-to-digital converter block 67 in the microcontroller 65, which takes a voltage from a reference resistor 69 at two additional inputs. The series-switched measurement leads 62A, 62B are switched in series with the reference resistor 69 (Rref) and are supplied with a constant current (I0) via a reference DC current source 68. current source") of the circuit module 64. The inputs of the ADU (German for "analog-to-digital converter") 67 detect, on the one hand, the measurement voltage drop on the measurement loop 62A, 62B in order to determine the resistance in relatively small ohmic series Rx by the current (I0), and on the other hand, according to the four-wire measurement principle, the voltage across the reference resistor 69 (Rref) is accurately determined from its ratio of the resistance Rx to be measured by the microcontroller 65.

To increase detection reliability, several measuring loops 62A, 62B can each be measured via their own differential amplifier 66 and a corresponding input of the ADU 67. As an alternative to the resistance value, it is of course also possible to equivalently determine a conductance. At the terminals M1 and M2 (FIG. 6B) of the circuit module 64, the measurement line is connected, that is, respectively a proximal end node of the measurement wires 62A, 62B near the base 2. The two distal end nodes of the measuring leads 62A, 62B are either short-circuited or connected to each other with low ohms. For standardization purposes, a temperature sensor 63 is connected to circuit module 64 (terminals T2 and T3).

The microcontroller 65 allows the ACTIVE LED to light green as soon as the circuit module 64 (via the and - terminals) is connected to a power supply (for example, 24 V DC) and the reference value is programmed . The reference value is programmed into the microcontroller 65 during power-up once through actuation of the SET button, through an initial measurement through the instrumentation amplifier 66 as indicated above.

The green and red ERROR LEDs illuminate as soon as the resistance value Rx, measured by the microcontroller 65, of the line has exceeded a predetermined warning threshold value (for example, 1.25 x Rx). The warning threshold value can be determined empirically from service life tests and, if necessary, can also be changed or updated later, for example via the communication module 7. Apart from that, the microcontroller 65 can close a warning message contact (O1) through an output by means of a relay (not shown).

If a wire break has occurred (Rx to infinity), for example, the green LED goes out and only the red ERROR LED lights up. Additionally, the microcontroller 65 then closes an additional potential-free fault contact (O2).

Preferably, the warning message is transmitted via a communication interface, for example an industrial bus, RS-232 or the like (3.3V, TX, GND) to the evaluation unit 6, optional in this case, or directly to a communication module 7 enabled for the Internet.

Through the communication interface (3.3V, TX, GND) of the circuit module 64, the microcontroller 65 can transmit detected measurement data (resistance value, constant current, voltage drop, temperature, etc.) to the unit. optional evaluation module 6 or directly to the communication module 7. Alternatively or Additionally, the circuit module 64 may feature a data logger (eg for a micro SD card) for storage of measurement data. Apart from that, sensor inputs can be provided as cycle counters or for position detection (eg according to FIGURES 1-5). A software filter may be implemented in the programming of the microcontroller 65 to filter out parasitic inductions, for example due to electromagnetic interaction with other live lines. Measurement of the resistance of the measurement leads 62A, 62B may be performed periodically, eg, every few minutes or at quasi-random time intervals, to avoid artifacts, eg, due to harmonic waves and the like.

FIGURE 7 shows, purely by way of example for illustration, how the measurement wires 62A, 62B are twisted together with the active supply wires in a supply cable 70, the measurement wires 62A, 62B being structurally identical to the minus other active supply wires during operation.

reference list

FIGURES 1-6

1 cable chain

1A stationary branch

1B mobile branch

1C Deflection curve

2 fixed point

4 Drag heel

5 guide channel

6 Evaluation unit

7 Communication module

FIGURES 1A-1B

10 Monitoring system

11 signal

12 indicator conductor

14 Circuit

FIGURES 2A-2B

20 Monitoring system

22 indicator conductor

22A, 22B Pilot wire

23 Short circuit component

24 Circuit

25 Microcontroller

26 Resonant Circuit

FIGURE 3

X Trailing heel position

Y Quantity (of the electrical magnitude)

30 Measured value (of the electrical quantity)

31 Lower tolerance curve

32 Upper tolerance curve

FIGURE 4

40 Supervision system

42 indicator conductor

42A, 42B Pilot wire

43 Short circuit component

44 Circuit

45 Microcontroller

46 Measurement resonant circuit

47 Reference resonant circuit (simulated)

48 Signal generator

49 Mixer step

FIGURE 5

50 Supervision system

51 signal

52 indicator conductor

54 Circuit

55 Oscillator (signal generator) 56 Demodulator

57 Comparator

59 end step

FIGURE 6

60 Supervision system

61 signal

62 Indicator Lead (Rx) 62A, 62B Pilot Wires

63 temperature sensor

64 circuit module

65 Microcontroller

66 Differential amplifier 67 Analog-digital converter 68 Current source

69 Reference resistor (Rref)

FIGURE 7

70 Power supply cable 72 Active wires

62A, 62B Pilot wires

Claims (14)

1. Monitoring system for monitoring the position of a cable chain (1) to guide at least one line between a base and a drag lug (4) that can move relative to it, comprising: - a chain cable carrier (1) which can be moved along a travel path and in this respect forms a mobile branch (1B) with a connection end for the drag lug (4), a static branch (1A) with a connection end for the base and a deflection curve (1C) between the two branches (1A; 1B); and - a monitoring device with at least one transmitter arranged on the cable chain (1), which evaluates a signal (11; 51) generated by the transmitter to monitor whether an error condition occurs during operation of the cable chain (1); the transmitter presenting an electrical indicator conductor (12; 22; 42; 52) guided by the cable-carrying chain (1), which runs at least along a predominant length of the mobile branch (1B); - the monitoring device comprises a circuit (14; 24; 44; 54) connected to the indicator conductor (12; 22; 42; 52), which detects an electrical magnitude by means of the indicator conductor (12; 22; 42; 52) ; characterized in that the monitoring system also has a generator (48; 55), which generates a time-varying drive signal, in particular an alternating current or pulse signal, and the circuit (14; 24; 44; 54) in the indicator conductor (12; 22; 42; 52) detects as a magnitude an electrical parameter sensitive to geometry with respect to the spatial position of the indicator conductor (12; 22; 42; 52). 2. Monitoring system according to claim 1, characterized in that the indicator conductor forms a receiving coil (42A, 42B), which is preferably displaceable with the moving branch (1B), and the circuit (44) works according to the principle of a metal detector. Monitoring system according to claim 2, characterized in that an additional transmitter coil is guided in the cable chain (1), in which the generator feeds the excitation signal. Monitoring system according to claim 1, 2 or 3, characterized in that the indicator conductor (22; 42; 52) forms a coil and in that the circuit detects an inductive parameter; where - at least one coil, in particular the receiving coil and/or the emitting coil, runs in a longitudinal section close to the trailing heel of the moving branch (1B) and/or - the cable chain (1) is guided in a ferromagnetic guide channel (5). Monitoring system according to claim 1, characterized in that the indicator conductor (22) is arranged as a loop antenna, in that the generator supplies the excitation signal to the indicator conductor (22) and in that the circuit (24) detects as magnitude a sensitive electrical parameter with respect to the geometry of the antenna. Monitoring system according to claim 1, characterized in that the indicator conductor (12) is arranged as a dipole antenna, in that the generator feeds the excitation signal to the indicator conductor (12) and in that the circuit (14) detects as magnitude a sensitive electrical parameter with respect to the geometry of the antenna. Monitoring system according to one of claims 1 to 6, characterized in that the monitoring device comprises an evaluation unit connected to the circuit. Monitoring system according to claim 7, characterized in that the evaluation unit (6) has a memory for application data, and comprises logic, which evaluates the signal emitted by the circuit (14; 24; 44; 54; 64) depending on the stored application data. Monitoring system according to one of Claims 7 to 8, characterized in that the evaluation unit (6) comprises a communication interface for connection to a higher-order system (7). Monitoring system according to one of Claims 1 to 9, characterized in that the monitoring device has a temperature sensor (63) for normalizing the temperature. Monitoring system according to one of claims 1 to 10, characterized in that a logic circuit (25; 45; 65) is provided, in particular a microcontroller, ASIC, DSP or the like, which digitally processes the electrical magnitude detected, in for comparison with a reference value from a reference value memory. Monitoring system according to one of claims 7 to 11, characterized in that the circuit (14; 24; 44; 54; 64), during continuous operation of the cable chain (1), constantly detects the electrical quantity in time or discrete in time and a filter, in particular a mean value filter or a peak filter, is provided in the circuit (14; 24; 44; 54; 64) or in the evaluation unit (6). Monitoring system according to one of Claims 1 to 12, characterized in that the monitoring device (10; 20; 40; 50; 60) is arranged stationary as a module on the base (2) and the or the indicator conductors (12; 22; 42; 52; 62) are or are connected to the circuit (14; 24; 44; 54; 64) on one side at the connection end for the base (2). Use of a monitoring system (10; 20; 40; 50) according to one of claims 1 to 13 for monitoring the spatial course of the energy chain (1) during continuous operation.